Indian Pacing Electrophysiol. J. 2002;2(2):40 Current Status of Internal Cardioversion in Atrial

For more than 30 years transthoracic external cardioversion has been an established method for the restoration of sinus rhythm in patients with persistent atrial fibrillation. It was first described by Lown in 19631. Though the success rate for external cardioversion ranges from 60-90 %2,3,4, there is reduced efficacy in those patients with a high body-mass index and an increased transthoracic diameter 5. The method of internal cardioversion for restoration of sinus rhythm using transvenous electrodes has been reported in several animal6,7 and human studies 8,9,10,11,12,13,14,15. Cooper et al6 tested multiple electrode configurations in a sheep model of atrial fibrillation. They demonstrated that the optimal single current pathway for internal atrial defibrillation employed two electrodes that surrounded both atria (e.g., right atrial appendage and distal coronary sinus). Similar results have been reported in several human studies12,13,14. Internal cardioversion has been shown to be superior to conventional external cardioversion in terms of primary success rate, energy requirements and the need for sedation; this superiority holds especially true for patients with a high body mass index of> 25 kg/m2 and increased transthoracic diameter